1. Field of the Invention
This invention relates to packaged integrated circuits and more particularly to an interconnected device which can be customized for stackably interconnecting leads of one packaged integrated circuit to leads of another packaged integrated circuit.
2. Description of the Relevant Art
Stacking of packaged integrated circuits (referred to herein as "components") is well known. Placing one component a spaced distance over another component minimizes the amount of circuit board area consumed by the stacked components. Instead of interconnecting leads laterally spaced from each other across a board, leads of stacked components are vertically interconnected. Exemplary stacking applications include memory expansion and microprocessor enhancement (e.g., stacking parallel processor components and/or coupling a high speed clocking component upon a processor component). Depending upon the application, stacking of components has provided add-on capability and has minimized circuit board usage.
There are many types of stacking techniques currently used. Described in U.S. Pat. No. 4,696,525 is a dual-in-line package ("DIP") which can be stacked upon another DIP using an interconnect device coupled therebetween. The interconnect device of U.S. Pat. No. 4,696,525 includes upwardly extending and downwardly extending contact arms which connect with leads on the upper and lower components, respectively. Once stacked, solder is dispensed at the contact points to retain electrical connection.
The solder joint between the upper and lower components of U.S. Pat. No. 4,696,525 proves a burden if rework is necessary in the field. Reworking a solder joint requires heating the joint, which implies access to the joint via a heat source. To avoid the cumbersome nature of such rework, it would be advantageous to use an interconnect device which does not require solder. A desirable interconnect device must therefore be connected together solely by fittings having frictional engagement, and must be connected between a lower component and an upper component with similar frictional engagement. The interconnect device must also be capable of interconnecting components of dissimilar geometries and dissimilar lead configurations. In the latter instance, a more optimal interconnect device must therefore be fully customizeable.
The advantages of a fully customizeable interconnect device are manyfold. The interconnect device must be capable of connecting one or more leads of a lower component to one or more leads of an upper component. As defined herein, a "lead" includes an electrical contact point extending from or arranged upon the component, and thereby encompasses contact points on what is often referred to as "leaded" or "leadless" components. The lower and upper components can therefore be any pair of packaged integrated circuits, including chip carriers, flat packs, small outline packages, pin-grid arrays (PGAs) and/or DIPs. To be fully customizeable, the interconnect device must be capable of interconnecting between any of the aforementioned leads extending from or residing on any of the aforementioned components.